iStat Menus is an advanced Mac system monitor, covering an enormous range of stats. It lives right in your Mac’s menubar, so detailed information is only ever a glance or single click away. iStat Menus 4 introduces an all-new, Retina display friendly design, per process network bandwidth monitoring, history graphs across the board, calendar events and much, much more.

CPURealtime CPU graphs and a list of the top 5 CPU resource hogs. CPU usage can be tracked by individual cores or with all cores combined, to save menubar space.

MemoryMemory stats for your menubar as a pie chart, graph, percentage, bar or any combination of those things. Opening the menu shows a list of the apps using the most memory, and other useful info.

NetworkA realtime graph to keep on top of what’s being sent and received for all network connections, including a bandwidth breakdown for the top 5 apps.

Disk UsageSee used and free space for multiple disks in your menubar. SMART status monitoring and more detail for all your disks is only a click away.

Disk ActivityDetailed disk I/O in your menubar, displayed as a graph, a variety of different read and write indicators, or both.

SensorsRealtime listings of the sensors in your Mac, including temperatures, hard drive temperatures (where supported), fans, voltages, current and power. Fan speeds can be controlled, with different rules when on battery power, if you’d like.

Date & TimeA highly configurable date, time and calendar for your menubar, including fuzzy clock and moon phase.Open iStat Menus’ calendar to display upcoming events, or events for any day. Plus, a world clock with sunrise, sunset, moonrise and moonset times for over 20,000 cities.

BatteryDetailed info on your battery’s current state and a highly configurable menu item that can change if you’re draining, charging, or completely charged.Plus, Magic Mouse, Magic Trackpad and Apple wireless keyboard battery levels.